The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A combustion cycle of an engine produces particulates that are typically filtered from exhaust gas by a particulate filter (PF). The PF is disposed in an exhaust system of the engine. Over time, the PF becomes full and trapped particulates from the PF must be removed. A regeneration process is performed to remove the particulates of the PF. The regeneration process ignites the particulates to initiate an exothermic reaction within the PF. The exothermic reaction propagates along the PF.
During a combustion cycle of an engine, an air/fuel mixture is compressed and ignited within a cylinder of the engine. To facilitate regeneration, fuel may be injected into the cylinder during the combustion cycle and after ignition of the air/fuel mixture. The injected fuel, referred to as post-injected (PI) fuel, may be introduced during ignition and/or exhaust strokes of the combustion cycle. The injected fuel exits the engine with the exhaust gas and is oxidized by an oxidation catalyst disposed in the exhaust system. The heat released from the oxidation reaction in the catalyst increases the temperature of the exhaust system, which facilitates the ignition of the particulates in the PF.
The post-injection of fuel may be adjusted to maintain a predetermined exhaust gas temperature. This improves fuel economy and regeneration efficiency. As an example, the post-injection of fuel may be adjusted based on a temperature of the exhaust, which may be detected via a temperature sensor. The adjustment of the PI fuel based on the temperature of exhaust gas provides limited exhaust gas temperature control and may result in either an under-fueling or over-fueling of the PI fuel.